Fluorine-containing sulfonylamide salts are a compound useful as an ion conductive material, and an electrolyte or an additive used in secondary batteries or the like (Patent Document 1, Patent Document 2).
It has been reported that the more impurities such as water, ash and SO42− contained in those salts are reduced, the higher the effect on discharge capacity and current efficiency in charge-discharge of secondary batteries becomes (Non-patent Document 1). Thus, methods for producing such salts in high purity have been developed.
For example, a method for producing high purity fluorosulfonylamide salt in which after fluorination reaction of chlorosulfonylamide or a salt thereof, the reaction solution is contacted with an alkaline aqueous solution to remove impurities has been proposed (Patent Document 3).